Need help with weird noise

[Johnny1988]

hey guys I need help with my precision acoustics tower speakers and my harmon kardon amplifier
I have a loud humming noise from the speakers when there is talking and certain music but the worst is a loud hum that happens when you suddenly stop the music any help would be much qppreciated

 

[Ponzio]

I would suspect a grounding issue, either at the electrical outlet or the H-K amp itself.

For giggles, get a long 3-prong electric cord and connect it to the H-K amp and then plug the other end to another electrical outlet in your house, not on the same circuit-breaker, to eliminate the outlet as the source of the issue, unless your whole electric service has a grounding issue, which I doubt.

 

[Johnny1988]

So i have done that and switched the outlet but its still doing the hum when there is sound present i suspect it is grounding on the amp itself id did not do it on my older prioneer

 

[lovinthehd]

So i have done that and switched the outlet but its still doing the hum when there is sound present i suspect it is grounding on the amp itself id did not do it on my older prioneer

Might want to go thru this for starters https://www.audioholics.com/home-theater-connection/ground-loops-eliminating-system-hum-and-buzz

 

[TLS Guy]

hey guys I need help with my precision acoustics tower speakers and my harmon kardon amplifier
I have a loud humming noise from the speakers when there is talking and certain music but the worst is a loud hum that happens when you suddenly stop the music any help would be much qppreciated

Disconnect the Harmon Kardon, from everything except the speakers and the AC mains.

If the unit hums, its broken. If it is quiet then you have a ground loop.

If quiet, then connect all input cables one by one and check for hum after each and every cable is connected. If hum comes back after connecting ANY cable, then that is the source of the ground loop.

Do what I just told you and report back, so we can further advise you.

 

[Johnny1988]

The only input I have is my digital optical so I'm looking at replacing the cable the sound hum is only present when there is background noise or sudden stops from the xbox

 

[TLS Guy]

The only input I have is my digital optical so I'm looking at replacing the cable the sound hum is only present when there is background noise or sudden stops from the xbox

How do you know the problem is not your xbox? So disconnect it and see if you have hum. You can't get a ground loop from an optical cable, but it can transmit hum. From what you say, my money is not on the xbox being the problem.

 

[highfigh]

How old is the Harman Kardon?

You wrote 'amplifier'- is that one piece, as in, an integrated amplifier, stereo receiver or AV receiver, or is it a preamp/power amp combination?

I agree- disconnect any input from any other device and leave it as only the amplifier and speakers. If it still hums, turn the power odd and disconnect the speakers so you can test it with headphones (earbuds will work just as well if they're able to deliver a hint of bass). You may need to get a 3.5mm to 1/4" adapter, but that's the only additional thing needed (unless you don't have ear buds).

If the hum stops when the speakers are disconnected, move the speakers and speaker wires.

If you have a subwoofer, that should have been included in the original post and in that case, disconnect it and the hum will probably stop. This means you need to use a different outlet or possibly, a wireless transmitter/receiver for the sub's signal if you can't use a different outlet.

 

[Johnny1988]

The harmon kardon is likely ten years old i purchased it from a pawn shop because it has hdmi but only supports 720p i do not have a subwoofer attached yet all i have is my 2 tower speakers i will definitely try the headphone solution